Diagraph LA/4700, User Manual, Page: 66 / 69

Diagraph - an ITW Company LA/4700 User Manual - Revision B
Pressure Sensor Adjustment Page 65
Pr
essur
e Sensor Adjustment
9.0 Pressure Sensor Adjustment
9.1 Pressure Sensor Setup
The Festo pressure sensor should be set at the factory, but it
may be necessary to change settings on occasion.
The sensor is used in a normally open mode, where the
absence of proper air pressure opens the sensor’s contacts,
and triggers the system. Begin by pressing (and releasing) the
Edit button (C), until a small “SP” is flashing on the screen
near area (F) on the sensor. This is the Set-Point for triggering
an air pressure out condition. Use arrow buttons (A) for
increasing and (B) for decreasing the set-point. The default
setting should be 60 PSI for operation with the LA/4700 unit.
Press the Edit button until the sensor returns to the main
screen.
Other settings found in this sequence are: trigger edge,
normally open or closed operation, setpoint, and hysteresis.
These should be left as rising edge, normally open, 60 PSI,
and 0.7 PSI, respectively.
When pressure is above the set-point, the light block with the
“A” above it will be illuminated (D). When pressure is below the set-point, this light will be off.
During normal operation, the display will show pressure digitally in area (E), and a bargraph will
show the same pressure in an analog fashion (F). This display can be used for diagnostics, as
well as capturing the pressure’s highs and lows during operation.
9.2 Checking Minimum and Maximum Pressures Detected
In troubleshooting an application, it may be desirable to determine if the supplied compressed air
has caused an intermittent error condition. Once the system detects that the pressure is too low
to reliably run, it will trigger an error and go offline. If the pressure is restored, it may appear that
the unit falsely triggered an error. The sensor maintains a record of the minimum and maximum
pressures experienced, but only as long as the power remains on. The first step is to clear the
min and max values captured, to avoid detecting a minimum pressure due to the air pressure
being shutoff. With OSHA shutoff in the open position, cycle power to the system by using the
screens on
page 44
. The values are now cleared and ready to capture the new highs and lows.
To view the values captured, press the Up button (A) on the sensor until the “min” flashes on the
display. This shows the minimum pressure captured on the digital display area (E). Press the
Edit button (C) momentarily; this will clear the value. Press the Up button again until the “max”
flashes on the display. This shows the maximum pressure captured. Press the Edit button (C)
momentarily; this will clear the value.
9.3 Defaulting the Sensor to Factory Settings
During the process of setting new values or making changes, mistakes can be made resulting in
improper operation of the sensor. To reset the sensor back to default settings, power off the
system by using the procedure on
page 44
. Turn the system back on while simultaneously
holding down the Up, Down, and Edit buttons (A, B, and C). This will reset the settings, but all of
the values specified in
Pressure Sensor Setup on page 65
must be entered.